If the task of a robot is basically common to a task performed by model commands with which the robot has already been instructed, it will be convenient for the operation to transform the already instructed model commands into executable commands and then operate the robot in accordance with the executable commands, instead of re-instructing the robot from the beginning; consequently, time needed to instruct the robot can be saved. In an extensive application of model commands, it will be advantageous if a plurality of command transforming programs are prepared so that one of the programs which meets the requirement of the operation is selected to generate executable commands. In this case, however, it becomes necessary to provide a switch or keys on the robot control panel so as to select a command transforming program. The robot control panel, in general, already has many switches and keys, and to avoid complication of the panel, it is not desirable to provide additional switches or keys. Selection of one of many keys for command transforming programs is awkward and apt to invite erroneous operation.